Long post! Opinions requested please!

I have been a baby-names lover for a long time and I never thought I would need to ask for help! But we really need to make a decision soon and we are really stuck. We just don't have a strong enough opinion on any of these names. We have TONS of girl names but no firm boy names.

So, please:
1. Comment on these names!
2. Suggest others in the same league/style...
3. Point out a potential problem (or why you think one is the clear winner)... but go easy on me ... please no serial-killer stories in case we end up using your name after all

Thanks for your opinions!

Here are the issues:

We are both teachers and we would like to use a name that is not common, preferably that we have never taught;

We really like old-man names and our daughter's name is kind of an old-lady name

Our daughter's first and middle names are both family names, but we don't like any of our family's male names nor any male versions of the female names - trust me, we have tried!

It really shouldn't end in "er" since the baby's last name will end in "er"

No cowboy names

We are using Theodore for a middle name so don't want to start with T for the first name

So, do you see a clear winner on the shortlist? And do you have other suggestions for first names that seem to go along with our list? I know that "Seamus" doesn't really fit the pattern, but we do like it for its uniqueness and brightness. The rest of the names are quite formal, I think.

Other possible things to consider:

Our daughter has a nature name so it'd be fun to have a nature-related or nature-meaning name

I'm a teacher too and my only real "rule" is no names of former students! I completely understand wanting a fresh name with no student association. From your list, I really like Felix and Linus! Here are other nature names to consider: Boyce, Caspian, Dylan, Mead, Sorrel, Walden. Best of luck!

I like your naming style a lot. There's not one that clearly wins out in my mind, but I think Solomon, Saul (would be a good stand alone name as well), Felix, Seamus and Linus (although the association to the Peanuts character is pretty strong, maybe not just a 'one person/character' name though, so it might still work) are all pretty cool. I do agree that Fievel could be a really cool name too (and it's got a great meaning), but to me it feels too much like a 'one character' name, like the mouse from American Tail has claimed it all for himself. Without knowing your daughters actual name, my guess is that Felix would probably be the best fit based on what you've said about her name. Your eliminated name list also has some pretty great names on it, in fact I quite like all of them (except for maybe Reuben and Raffi).
Here are some other suggestions, based on what seems to be your taste:RolandLelandAmiasBoazZaneDanteConradEzioAldousCorneliusDesmondOrenLionelOswinDariusJarvisEamon

SolomonTheodore is a mouthful. If Theodore stays as a middle, I don't like any of your top choices flow wise with this middle name. Sorry. Detest Feivel, jokes abound and he can never be taken seriously in my mind. AmosTheodore sounds very nice and approachable off of your list. Otherwise, for other options: